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B.1.46
Evaluation of LOG(x)
Floating-point evaluation of log
cand and e is the unbiased exponent. Then, log
log
(s) can be evaluated with a polynomial. By adding the unbiased exponent, log
2
execution speeds and accuracies may be determined by using different order polynomials.
page
org
polyc
dc
dc
dc
dc
dc
dc
dc
dc
dc
org
;
;
calculate d2=log2(d0)
;
getexp
fgetman
fclr
do
fmpy.x
fadd.x
_log2sig
float.x
fadd.s
MOTOROLA
(x) can be performed by representing x as s * (2 ** e) where s is the signifi-
2
(s * (2 ** e)) = log
2
132,60,1,1
x:0
0.6681523e-02
-0.6736254e-01
0.2584541e+00
-0.3676691e+00
-0.4461204e+00
0.2740512e+01
-0.5236615e+01
0.6184454e+01
-0.3072334e+01
p:$100
d0,d7
#polyc,r0
d0,d0
d2
x:(r0)+,d1.s
#9,_log2sig
d2,d0,d2
d1,d2
x:(r0)+,d1.s
d7
d7,d2
DSP96002 USER'S MANUAL
(s) + e. After extracting the significand s,
2
; ** 8
; ** 7
; ** 6
; ** 5
; ** 4
; ** 3
; ** 2
; ** 1
; ** 0
Totals:
(x) results. Various
2
Program
ICycles
Words
2
2
1
1
1
1
2
3
1
1
1
1
1
1
1
1
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27
B-115
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